North African theologian and philosopher whose Confessions and City of God shaped Western Christianity's understanding of sin, grace, free will, time, and the relationship between the church and political power — making him the most influential Christian thinker between Paul and the Reformation.
Augustine invented the interior life as a subject for literature. He was the first writer to describe the inner experience of spiritual struggle in a way that still feels modern — the divided will, the inability to do what you know is right, the experience of grace as something that happens to you rather than something you achieve. Sixteen centuries later, the framework is still in use.